Facile method for spectroscopic examination of radical ions of hydrophilic carotenoids

K. Razi Naqvi, Thor Bernt Melø, Tamás Jávorfi, Sergio González-Pérez, Juan B. Arellano
2009 Physical Chemistry, Chemical Physics - PCCP  
Hydrophilic carotenoids, unusual members of an intrinsically hydrophobic family, and their radical ions are important reactants. An all-optical method for generating singly charged radical ions of a hydrophilic carotenoid (Car) is described. It relies on photolyzing an aqueous mixture of Car and a photoionizable auxiliary solute (A), and making conditions conducive to the capture, by Car, of the hydrated electron (e À aq ) or the positive hole in A + or both. When A is Trolox (TOH), only e À aq
more » ... (TOH), only e À aq can be captured, since TOH + deprotonates too rapidly to be a hole donor; when A is Trolox methyl ether (TOMe), both Car À and Car + are formed, since TOMe + lives long enough to transfer its positive hole to Car; formation of Car À is prevented under aerobic conditions.
doi:10.1039/b905454e pmid:19809671 fatcat:kf74y5jquvhphk2cc5mxdslvfm